The present invention relates to a sheet metal follower for a bending press, the press presenting a fixed bottom table carrying a bending matrix on its top face, and the follower being of the type comprising:
a follower table capable of pivoting about a horizontal pivot shaft at its front end;
a lateral transfer carriage mounted on the front wall of the fixed bottom table so as to be capable of moving horizontally along said front wall;
a vertical support wall secured to the transfer carriage and provided with vertical slideways and at least one vertical ball screw suitable for being rotated from its bottom end;
a support structure presenting a vertical front plate and two vertical side plates extending away from the bottom table of the press;
vertical guide rails secured to the front plate of the support structure and each co-operating with a corresponding slideway of the carriage support wall, and a drive mechanism for driving the front plate of the support structure vertically;
a follower table hinged to the support structure about a horizontal shaft parallel to the bending matrix; and
means carried by said support structure suitable for causing said follower table to pivot about its shaft.
A follower table of this type is known from patent JP 10 31 526. Ignoring its complicated structure due to the two support structures nested one in the other and hinged about a common horizontal pivot shaft for the follower table, that shaft is nevertheless too far away from the bending matrix to be capable of ensuring that the follower table can perform pivoting that is always centered on the bottom of the matrix.
Furthermore, the combined use of toothed wheels, of actuators, and of levers requires precision assembly which is difficult to perform in the first place and difficult to maintain in service.
An object of the present invention is to eliminate or at least attenuate the drawbacks associated with the prior art and to propose a sheet metal follower of the above-specified type which can be put into position quickly and accurately and in which the pivot axis for the follower table is very close to the bending matrix.
This object is achieved by the fact that there are provided:
at the top end of each of the vertical side plates of the support structure, a respective pair of bearings that are spaced apart from each other, having axes that are horizontal, in alignment with each other, and perpendicular to the vertical front plate of said structure;
two-depth adjustment columns each slidably received in a corresponding pair of bearings;
a transverse vertical arm rigidly interconnecting the front ends of the two adjustment columns, and secured on the top face of the support structure that is raised relative to the top ends of the side plates to support fingers whose front ends have respective bearings for the horizontal pivot shaft of the follower table which, by means of its center and rear portions, covers the support structure and the members secured thereto;
a rectilinear guide member provided in the center portion of the follower table beneath the plane top wall thereof and extending in the vertical midplane of the table perpendicularly to its pivot shaft;
a hinge fork suitable for sliding on the rectilinear guide member and carrying a horizontal axis parallel to the pivot shaft;
a ball wormscrew whose top head is hinged to the fork via a connection pin parallel to the pivot of the follower table;
a pivot cage fixed on either side on one of the vertical plates of the support structure so as to be capable of pivoting about a horizontal axis parallel to the pivot shaft of the follower table and disposed close to the top end of said structure; and
a nut co-operating with the wormscrew and secured to the cage in axial displacement but being free to move in rotation relative thereto, and a motor secured to the cage and having its outlet shaft parallel to the wormscrew and rotating said nut by means of a cog belt.
In other words, the sheet metal follower thus comprises a follower table which is associated with means enabling it to perform rectilinear movements in three mutually perpendicular directions plus a pivoting movement about its front shaft parallel to the greatest extent of the bending matrix, said means comprising horizontal transfer means parallel to the front wall of the fixed bottom table of the bending press and to the greatest extent of the bending matrix, vertical displacement means carried by the transfer means and secured to a support structure of the follower table, horizontal displacement means for moving the follower table horizontally relative to its support structure and perpendicularly to the pivot shaft of said follower table, and means for pivoting said table about its pivot shaft, said pivot means being of variable length between its hinge on the support structure and its hinge on the follower table, which hinge is capable of sliding along the follower table in a direction perpendicular to the pivot shaft of said table.
By means of this design, the follower table can be put into position relative to the bending matrix quickly and accurately while avoiding elements that are complicated and expensive to manufacture.